Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0407—Constructional details of adsorbing systems
  • B01D53/0446—Means for feeding or distributing gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0407—Constructional details of adsorbing systems
  • B01D53/0438—Cooling or heating systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/38—Removing components of undefined structure
  • B01D53/44—Organic components
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/102—Carbon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
  • B01D2253/108—Zeolites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2259/00—Type of treatment
  • B01D2259/40—Further details for adsorption processes and devices
  • B01D2259/40083—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption
  • B01D2259/40088—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by heating
  • B01D2259/4009—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by heating using hot gas

Definitions

• the present invention relates to an organic solvent recovery system.
• Patent Document 1 discloses a gas treatment device that includes three treatment tanks, a treated gas supply section, a connecting flow path, a water vapor supply section, and a dilution gas supply path.
• Patent Document 2 discloses an organic solvent recovery system that includes a first adsorption/desorption device having two treatment tanks, and a second adsorption/desorption device that recovers organic solvents contained in the treated gas discharged from one of the treatment tanks of the first adsorption/desorption device.
• the adsorption process is carried out continuously in two treatment tanks, thereby increasing the organic solvent removal rate
• the organic solvent recovery system described in Patent Document 2 the adsorption process is carried out continuously in one of the treatment tanks of the first adsorption/desorption device and the first processing section of the second adsorption/desorption device, thereby increasing the organic solvent removal rate.
• steam mist (hereinafter, white smoke) that is generated immediately after switching between the adsorption and desorption processes in the treatment tank may be mixed into the gas to be treated that is discharged from the treatment tank of the first adsorption/desorption device and supplied to the second adsorption/desorption device for several tens of seconds immediately after switching.
• the adsorbent of the second adsorption/desorption device When the adsorbent of the second adsorption/desorption device has adsorbed a certain amount or more of the organic solvent in the gas to be treated (i.e., the adsorption process of the second adsorption/desorption device has been performed for several minutes), if a high-temperature, high-humidity gas to be treated that contains white smoke is supplied to the second adsorption/desorption device, the adsorption rate of the organic solvent slows due to the rise in the temperature of the gas to be treated and the adsorption of moisture to the adsorbent of the second adsorption/desorption device, causing a problem that organic solvent gas at a concentration greater than the designed outlet concentration of the second adsorption/desorption device is discharged into the treatment gas.
• the adsorption of moisture by the white smoke also causes an increase in the thermal energy required for the desorption process of the second adsorption/desorption device.
• One way to deal with the effects of white smoke is to cool and dehumidify the gas being treated, but this requires larger cooling equipment, which in turn increases the size of the device.
• the organic solvent gas concentration contained in the treatment gas immediately before switching from the adsorption process to the desorption process is generally relatively high compared to the organic solvent gas concentration contained in the treatment gas at the start of the adsorption process. This is because the adsorbent of the first adsorption/desorption device sufficiently adsorbs the organic solvent gas, and the unused adsorption capacity gradually decreases, causing the adsorption rate to decrease. Therefore, a design is required that can process this high organic solvent gas concentration, which creates the problem of the device becoming larger.
• the present invention has been made in consideration of the above problems, and its purpose is to provide an organic solvent recovery system that does not reduce processing performance and can prevent the system from becoming larger.
• the present invention has the following configuration.
• the organic solvent recovery system of the present invention includes a plurality of organic solvent recovery devices each including a first adsorbent capable of adsorbing and desorbing an organic solvent, and a plurality of treatment tanks alternately performing an adsorption process in which the organic solvent contained in an introduced gas to be treated is adsorbed by the first adsorbent and a first treatment gas is discharged, and a desorption process in which the organic solvent is desorbed from the first adsorbent by introduced water vapor and a desorbed gas is discharged, the plurality of treatment tanks being selected from the plurality of treatment tanks, and an extraction flow path for discharging the first treatment gas from the treatment tank; an organic solvent concentrating device having a second adsorbent capable of adsorbing and desorbing the organic solvent, adsorbing the organic solvent contained in the first treated gas discharged from the organic solvent recovery device, discharging a second treated gas, and desorbing the adsorbed organic solvent from the second adsorbent and discharging it
• the organic solvent recovery system may include three or more of the treatment tanks and a connecting flow path that connects a selected number of the treatment tanks from among all of the treatment tanks in series in multiple stages, and may perform the adsorption process in the multiple treatment tanks connected in series in multiple stages to discharge the first treatment gas, and perform the desorption process using the water vapor in the remaining treatment tanks, and may further include a dilution gas supply flow path that supplies a dilution gas to the connecting flow path.
• the organic solvent recovery system may include a return flow path that returns the concentrated gas desorbed from the second adsorbent to the diluted gas supply flow path.
• the organic solvent recovery system may include a return flow path that returns the concentrated gas desorbed from the second adsorbent to a treated gas supply flow path that introduces the treated gas into the organic solvent recovery device.
• the second adsorbent may be made of a material containing at least one of granular activated carbon, activated carbon fiber, or zeolite.
• the organic solvent recovery system may use heated air for desorption in the second adsorbent.
• the organic solvent recovery system may include a connection flow path that introduces a portion of the second treatment gas into the second adsorbent for use in desorbing the organic solvent from the second adsorbent, and a heating unit provided in the connection flow path.
• the present invention makes it possible to miniaturize the organic solvent recovery system by configuring a system in which the process gases from multiple organic solvent recovery devices are treated in an organic solvent concentrator. Furthermore, by operating the system in such a way that the adsorption and desorption process switching in the treatment tank of one organic solvent recovery device and the adsorption and desorption process switching in the treatment tank of the other organic solvent recovery device do not occur simultaneously, when one organic solvent recovery device discharges process gas containing white smoke, the other discharges process gas not containing white smoke, and the two process gases join together and are introduced into the organic solvent concentrator.
• 1 is a diagram showing an example of a configuration of an organic solvent recovery system according to an embodiment of the present invention.
• 1 is a diagram showing an example of a configuration of an organic solvent recovery system according to an embodiment of the present invention.
• 1 is a table showing the difference in temperature of the gas to be treated that contains white smoke and is introduced into an organic solvent concentrating device and the difference in temperature required for cooling in an embodiment and a comparative example.
• 1 is a table showing the dichloromethane concentration in the gas to be treated introduced into an organic solvent concentrating device and the dichloromethane concentration in the gas treated by the organic solvent concentrating device in the examples and comparative examples.
• FIGS. 1 and 2 are diagrams each showing a schematic configuration of an organic solvent recovery system 1A, 1B according to an embodiment of the present invention. The following description will be given of a case in which two organic solvent recovery devices 100 are provided.
• the organic solvent recovery systems 1A, 1B include an organic solvent recovery device 100, an organic solvent concentrating device 200 (200A, 200B), a feed flow path 300, and a return flow path 400.
• the organic solvent recovery systems 1A, 1B are a system in which the organic solvent is removed and recovered from a gas to be treated containing the organic solvent in the organic solvent recovery device 100, and then the organic solvent is further removed and concentrated in the organic solvent concentrating device 200 (200A, 200B) from the first treated gas discharged from the organic solvent recovery device 100, and the concentrated gas discharged from the organic solvent concentrating device 200 (200A, 200B) is returned to the organic solvent recovery device 100 again through the return flow path 400.
• the organic solvent recovery apparatus 100 is an apparatus for removing and recovering organic solvents from gas to be treated.
• the gas to be treated is supplied to the organic solvent recovery apparatus 100 from a gas to be treated supply source provided outside the system of the organic solvent recovery apparatus 100.
• the organic solvent recovery apparatus 100 has three treatment tanks 101-103, a gas to be treated supply flow path L110, connecting flow paths L121-L123, extraction flow paths L131-L133, steam supply flow paths L141-L143, organic solvent recovery flow paths L151-L153, a separator 120, a re-supply flow path L160, and a dilution gas supply flow path L170.
• Each treatment tank 101-103 has a first adsorbent 101A-103A capable of adsorbing and desorbing organic solvents.
• the first adsorbents 101A-103A can be granular activated carbon, zeolite, honeycomb-shaped activated carbon, zeolite, or activated carbon fiber, with activated carbon fiber being preferred.
• Each treatment tank 101-103 has an opening/closing damper V101-V103 that switches between supplying and not supplying the treated gas to the treated gas supply port, and an opening/closing damper V104-V106 that switches between discharging and not discharging the treated gas from the discharge port after it has passed through the first adsorbent 101A-103A.
• the adsorption of the organic solvent by the first adsorbent 101A-103A and the desorption of the organic solvent from the first adsorbent 101A-103A are alternately performed. That is, in one of the three treatment tanks 101-103, a first adsorption process is performed in which the first adsorbent adsorbs the organic solvent from the gas to be treated supplied from the gas to be treated supply source, and in another of the three treatment tanks 101-103, a second adsorption process is performed in which the first adsorbent adsorbs the organic solvent from the gas to be treated after being treated in the treatment tank used in the first adsorption process (hereinafter referred to as the first adsorption process gas) and the first treatment gas is discharged, and during that time, a desorption process is performed in the remaining treatment tank in which the organic solvent is desorbed from the first adsorbent. In each of the treatment tanks 101-103, the desorption process, the second adsorption process is performed in which the
• the treated gas supply flow path L110 is a flow path for supplying the treated gas to each of the treatment tanks 101 to 103.
• the upstream end of the treated gas supply flow path L110 is connected to a treated gas supply source.
• the treated gas supply flow path L110 is provided with a cooler C1 and a heater H1 for adjusting the temperature and humidity of the treated gas flowing into each of the treatment tanks 101 to 103.
• the treated gas supply flow path L110 has branch flow paths L111-L113 that supply the treated gas to each of the treatment tanks 101-103.
• the branch flow path L111 is provided with an on-off valve V111.
• the branch flow path L112 is provided with an on-off valve V112.
• the branch flow path L113 is provided with an on-off valve V113.
• the branch flow paths L111-L113 are connected to the treated gas supply ports of each of the treatment tanks 101-103.
• Each of the exhaust flow paths L181 to L183 is connected to each of the three treatment tanks 101 to 103.
• the treated gas introduced into the treatment tank 101 is discharged from the exhaust flow path L181 as a first adsorption process gas by the first adsorption process.
• the discharged first adsorption process gas is transported to the connecting flow path L121 through the dilution gas supply flow path L170 and the merging path L120.
• the connecting flow path L121 is connected to the branch flow path 112, and introduces the first adsorption process gas into the treated gas supply port of the treatment tank 102 to perform the second adsorption process.
• the first adsorption process gas is discharged from the exhaust flow path L182 and is passed through the connecting flow path L122 to perform the second adsorption process in the treatment tank 103.
• the first adsorption process gas is discharged from the discharge flow path L183 and passes through the connecting flow path L123 to perform the second adsorption process in the treatment tank 101.
• Each of the connecting flow paths L121 to L123 has a junction path L120 where they merge with each other.
• An on-off valve V121 is provided at the portion of the connecting flow path L121 where it branches off again from the junction path L120.
• An on-off valve V122 is provided at the portion of the connecting flow path L122 where it branches off again from the junction path L120.
• An on-off valve V123 is provided at the portion of the connecting flow path L123 where it branches off again from the junction path L120.
• the extraction flow paths L131 to L133 are flow paths for extracting the first treated gas, which is the treated gas after being adsorbed in each of the treatment tanks 101 to 103.
• the extraction flow paths L131 to L133 are connected to the treated gas exhaust ports in each of the treatment tanks 101 to 103.
• An on-off valve V131 is provided in the extraction flow path L131.
• An on-off valve V132 is provided in the extraction flow path L132.
• An on-off valve V133 is provided in the extraction flow path L133.
• Each of the extraction flow paths L131 to L133 has a junction flow path L130 where they merge with each other.
• the water vapor supply flow paths L141 to L143 are flow paths for supplying water vapor to each of the treatment tanks 101 to 103 in order to desorb the organic solvent adsorbed in the first adsorbents 101A to 103A from the first adsorbents 101A to 103A.
• the water vapor supply flow path L141 connects the water vapor supply source to the treatment tank 101, and is provided with an on-off valve V141.
• the water vapor supply flow path L142 connects the water vapor supply source to the treatment tank 102, and is provided with an on-off valve V142.
• the water vapor supply flow path L143 connects the water vapor supply source to the treatment tank 103, and is provided with an on-off valve V143.
• Each of the water vapor supply flow paths L141 to L143 has a water vapor supply flow path L140 that merges with each other.
• the organic solvent recovery flow paths L151 to L153 are flow paths for recovering water vapor (desorbed gas) containing the organic solvent desorbed from the first adsorbents 101A to 103A.
• Each of the organic solvent recovery flow paths L151 to L153 is connected to each of the treatment tanks 101 to 103.
• Each of the organic solvent recovery flow paths L151 to L153 has L150 where they merge.
• a condenser 122 is provided in the merge flow path L150. The condenser 122 condenses the desorbed gas by cooling the desorbed gas flowing through the merge flow path L150, and discharges the condensed liquid (a mixture of water generated by condensation of the desorbed gas and liquid-phase organic solvent).
• Separator 120 is provided downstream of junction flow path L150. After the condensate flows into separator 120, the condensate undergoes phase separation into a liquid phase of separated wastewater and a liquid phase of recovered solvent, and the recovered solvent is removed from the organic solvent recovery device 100. A space (vent gas) containing traces of organic solvent is formed above separator 120.
• the resupply flow path L160 is a flow path that connects the separator 120 and the treated gas supply flow path L110.
• the vent gas in the separator 120 is supplied again to each of the treatment tanks 101 to 103 through the resupply flow path L160 and the treated gas supply flow path L110.
• the wastewater treatment equipment 130 is equipment that removes organic solvents contained in the separated wastewater. It is supplied from the liquid phase of the separated wastewater of the separator 120, removes the organic solvents from the separated wastewater, and discharges the treated water outside the system.
• a specific example of the wastewater treatment equipment 130 is an aeration equipment that aerates the separated wastewater to volatilize the organic solvents contained in the separated wastewater and separates it into an aeration gas containing the organic solvents and treated water.
• the aeration gas is connected to the upstream side of the cooler C1 of the treated gas supply flow path L110 via the aeration gas supply flow path L161.
• the aeration gas supply flow path may be provided with a dehumidification means for removing moisture from the aeration gas.
• the dilution gas supply flow path L170 is a flow path for supplying the dilution gas to the connecting flow paths L121-L123 to promote drying of the first adsorbents 101A-103A after the desorption process.
• the dilution gas is composed of at least one of the following gases: outside air, instrument air, nitrogen gas, and argon gas.
• the organic solvent concentrating device 200 will be described with reference to 200A in FIG. 1 and 200B in FIG. 1 is provided with an organic solvent concentrating apparatus 200A, which is equipment for further removing organic solvent from the first treated gas discharged from the organic solvent recovery apparatus 100.
• the organic solvent concentrating apparatus 200A has a rotor-type adsorption/desorption treatment apparatus including a second adsorbent 201C that adsorbs and desorbs the organic solvent, and the second adsorbent 201C is divided into an adsorption zone that adsorbs the organic solvent and a desorption zone that desorbs the adsorbed organic solvent.
• the first treated gas discharged from the two organic solvent recovery devices 100 passes through the feed flow path 300, cooler C2, and heater H2, and through the adsorption zone of the second adsorbent 201C, whereby a second treated gas, which is a clean gas from which the organic solvent has been further removed, can be discharged.
• a smaller amount of heated gas than the first treated gas is passed through the desorption zone to desorb the organic solvent adsorbed by the adsorbent, thereby discharging a concentrated gas in which the organic solvent has been concentrated.
• the concentrated gas is returned to the organic solvent recovery device 100 from the diluted gas supply flow path L170 connected to the return flow path 400.
• the second adsorbent 201C is made of an adsorbent having a generally cylindrical outer shape, or an adsorbent arranged to form a generally cylindrical shape.
• the organic solvent concentration device 200A is provided with a motor, and when the motor is driven, the second adsorbent 201C rotates in the tangential direction, and any part of the second adsorbent 201C moves alternately between the adsorption zone and the desorption zone in time, performing the adsorption and desorption process.
• the second adsorbent 201C is composed of an adsorbent material containing any one of activated alumina, silica gel, activated carbon, and zeolite, but activated carbon and zeolite in granular, powder, honeycomb, etc. are preferred.
• the organic solvent concentration device 200A discharges the second treated gas discharged from the adsorption zone of the second adsorbent 201C to the outside through the clean gas discharge flow path L220.
• the organic solvent concentrating device 200A has a connecting flow path L230 and a heater H3.
• connection flow path L230 connects the clean gas discharge flow path L220 to the downstream of the adsorption zone, and a portion of the second treatment gas is used for desorption. Note that a configuration in which outside air is used for desorption may also be used.
• the organic solvent concentrating device 200B provided in the organic solvent recovery system 1B shown in FIG. 2 is a device for further removing organic solvent from the first treated gas discharged from the organic solvent recovery device 100.
• the organic solvent concentrating device 200B has at least two or more treatment tanks. In two cases, the treatment tanks 201 and 202 have second adsorbents 201A and 202A capable of adsorbing the organic solvent contained in the first treated gas discharged from the branch flow paths L211 and L212 through the confluence flow path L130.
• the second adsorbent 201A adsorbs the organic solvent contained in the first treated gas, while the treatment tank 202 desorbs the organic solvent in the first treated gas adsorbed by the second adsorbent 202A.
• the treatment tanks 201 and 202 perform the adsorption process and the desorption process in sequence, alternating between each other.
• the organic solvent is further removed, and the second treatment gas, which is a clean gas, can be discharged from the connecting flow paths L221, 222 connected to the treatment tanks 201, 202, respectively.
• a smaller amount of heated gas than the first treatment gas is passed through to desorb the organic solvent adsorbed by the adsorbent, and a concentrated gas in which the organic solvent is concentrated is discharged.
• the concentrated gas is returned to the organic solvent recovery device 100 from the dilution gas supply flow path L170 connected to the return flow path 400.
• An on-off valve V211 is provided in the branch flow path L211.
• An on-off valve V212 is provided in the branch flow path L212.
• An on-off valve V221 is provided in the connecting flow path L221.
• An on-off valve V222 is provided in the connecting flow path L222.
• Each treatment tank 201, 202 has a second adsorbent 201A, 202A capable of adsorbing and desorbing organic solvents.
• the second adsorbent 201A, 202A can be granular activated carbon, zeolite, honeycomb-shaped activated carbon, zeolite, or activated carbon fiber, with activated carbon fiber being preferred.
• Each treatment tank 201, 202 has an opening/closing damper V201, V202 that switches between supplying and not supplying the treated gas to the treated gas supply port, and an opening/closing damper V203, V204 that switches between discharging and not discharging the treated gas from the discharge port after passing through the second adsorbent 201A, 202A.
• the organic solvent concentrating device 200B discharges the second treated gas discharged from the treatment tank to the outside through the clean gas discharge flow path L220.
• the organic solvent concentrating device 200B has a connecting flow path L230 and a heater H3.
• connection flow path L230 connects the clean gas exhaust flow path L220 and the treatment tank, and uses a portion of the second treatment gas for desorption. Note that a configuration in which outside air is used for desorption may also be used.
• the connection flow path L230 branches into connection flow paths L231 and L232, which are connected to the treatment tanks 201 and 202, respectively.
• An on-off valve V231 is provided in the connection flow path L231.
• An on-off valve V232 is provided in the connection flow path L232.
• the organic solvent recovery flow paths L241, L242 are flow paths for recovering water vapor (desorbed gas) containing the organic solvent desorbed from the second adsorbents 201A, 202A.
• Each organic solvent recovery flow path L241, L242 is connected to each treatment tank 201, 202.
• Each organic solvent recovery flow path L241, L242 has a return flow path 400 that merges with each other.
• the feed flow path 300 is a flow path for sending the gas to be treated from the organic solvent recovery device 100 to the organic solvent concentration device 200.
• the feed flow path 300 is provided with a cooler C2 and a heater H2 for adjusting the temperature and humidity of the first treated gas to be introduced into the organic solvent concentration device 200.
• the return flow path 400 is a flow path for returning concentrated gas from the organic solvent concentration device 200 to the organic solvent recovery device 100.
• the return flow path 400 is connected to the diluted gas supply flow path L170.
• the two organic solvent recovery devices 100 should be provided with appropriate damper control devices as necessary to prevent simultaneous switching between the treatment tanks.
• the organic compounds contained in the gas to be treated by the organic solvent recovery system 1A, 1B of this embodiment are not particularly limited, but include aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and acrolein; ketones such as methyl ethyl ketone, diacetyl, methyl isobutyl ketone, and acetone; esters such as 1,4-dioxane, 2-methyl-1,3-dioxolane, 1,3-dioxolane, tetrahydrofuran, methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; alcohols such as ethanol, n-propyl alcohol, isopropyl alcohol, and butanol.
• aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and acrolein
• ketones such as methyl eth
• Examples include ethanol, glycols such as ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol, organic acids such as acetic acid and propionic acid, phenols, aromatic organic compounds such as toluene, xylene, and cyclohexane, ethers such as diethyl ether and allyl glycidyl ether, nitriles such as acrylonitrile, chlorine organic compounds such as dichloromethane, 1,2-dichloroethane, trichloroethylene, and epichlorohydrin, and organic compounds such as N-methyl-2-pyrrolidone, dimethylacetamide, and N,N-dimethylformamide.
• the gas to be treated may contain one or more of these.
• Example 1 The following treatment was carried out using the organic solvent recovery system 1A shown in Fig. 1 described above.
• An organic solvent-containing gas which is an example of the gas to be treated, was treated at 25°C and contained 26,000 ppm of dichloromethane at an air volume of 5.3 Nm3/min (per organic solvent recovery device), and the design concentration of dichloromethane discharged outside the organic solvent recovery system was 5 ppm or less.
• the gas to be treated was treated in two organic solvent recovery devices 100.
• Activated carbon fiber was used as the first adsorbent.
• Air was sent to the treatment tank 101, which was the first adsorption step, at an air volume of 5.3 Nm 3 /min (per organic solvent recovery device).
• the first adsorption step gas discharged from the treatment tank 101 was then sent to the treatment tank 102, which was the second adsorption step.
• the first adsorption step gas was adjusted to 9.5 Nm 3 /min and 45°C using dilution gas and concentrated gas.
• the gas treated in the treatment tank 102 was discharged as the first treatment gas and sent to the organic solvent concentration device 200 through the feed flow path 300.
• each step was switched. At this time, the switching between each step of the two organic solvent concentration devices was adjusted so that the switching timing was shifted by half the time of the adsorption step.
• treatment tank 101 was performing the first adsorption process and treatment tank 102 was performing the second adsorption process, desorption steam was introduced into treatment tank 103 to perform the desorption process.
• white smoke was present for one minute immediately after the adsorption tanks were switched, and the gas temperature after the two first treatment gases were joined was 50°C, the humidity was 100%, and the maximum concentration of dichloromethane in the first treatment gas was 50 ppm.
• Activated carbon fiber was used as the second adsorbent 201A of the organic solvent concentration device 200A.
• the first treated gas discharged from the organic solvent recovery device 100 was passed through the adsorption zone, and the second treated gas was discharged. A portion of the second treated gas was also fed to heater H3 via L230, superheated to 130°C, and supplied to the desorption zone, and the concentrated gas was discharged. The entire amount of concentrated gas was supplied to the diluted gas supply flow path L170 of the organic solvent recovery device 100 through the return flow path 400. The dichloromethane concentration in the second treated gas at this time was 5 ppm or less.
• the amount of activated carbon fiber used as the first adsorbent in the organic solvent recovery device 100 was 3.8 kg/tank, and the amount of activated carbon fiber used as the first adsorbent in the organic solvent concentration device 200A was 0.8 kg/device.
• the gas contained white smoke for one minute immediately after the adsorption tank was switched, and after the two first treated gases merged, the gas temperature was 60°C, the humidity was 100%, and the maximum concentration of dichloromethane in the first treated gas was 100 ppm. Also, the dichloromethane concentration in the second treated gas at this time was less than 5 ppm.
• the embodiment prevents simultaneous switching of the treatment tanks of the two organic solvent concentration devices, thereby suppressing the rise in gas temperature caused by the inflow of white smoke, thereby reducing the temperature required to cool the gas and making it possible to miniaturize the cooling equipment.
• the maximum concentration of dichloromethane in the first treatment gas can be suppressed by leveling out, which shows that it is also possible to miniaturize the organic solvent concentration device.
• the present invention can greatly contribute to the industrial world by controlling the switching between the processes of multiple organic solvent recovery devices in an organic solvent recovery system so that they do not occur simultaneously, making it possible not only to reduce the size of the cooling equipment required to prevent white smoke, but also to reduce the size of the organic solvent concentration device in the system.
• 1A, 1B organic solvent recovery system
• 100 organic solvent recovery device
• 101-103 treatment tank
• 101A-103A first adsorbent
• 120 separator
• 122 condenser
• 130 wastewater treatment equipment
• 200, 200A, 200B organic solvent concentration device
• 201, 202 treatment tank
• 201A, 202A, 201C second adsorbent
• 300 feed flow path
• 400 return flow path
• H1-H3 heater (heating section)
• C1, C2 cooler
• L110 treated gas supply flow path
• L120, L130, L150 merging path
• L121-L123, L2 21, L222 Connection flow path
• L131-L133 Extraction flow path
• L140-L143 Steam supply flow path
• L151-L153, L241, L242 Organic solvent recovery flow path
• L161 Aeration gas supply flow path
• L170 Dilution gas supply flow path

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• Separation Of Gases By Adsorption (AREA)

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• 2023
  • 2023-09-22 CN CN202380068915.3A patent/CN119894589A/zh active Pending
  • 2023-09-22 WO PCT/JP2023/034487 patent/WO2024070943A1/ja not_active Ceased
  • 2023-09-22 KR KR1020257013175A patent/KR20250086649A/ko active Pending
  • 2023-09-22 JP JP2024505627A patent/JPWO2024070943A1/ja active Pending
  • 2023-09-26 TW TW112136726A patent/TW202432225A/zh unknown

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